Cold pilger rollers are used to draw out a rough-pierced tube blank over a fixed mandrel, while two grooved rollers, which grasp the blank from above and below, perform back and forth rolling contact at regular intervals. The rollers maintain their motion relative to the roll stand, in which the rollers are mounted by means of bearings. The rollers are rotated with changing rotation direction, in their back and forth motion, by means of two racks mounted thereon engaging two pinions mounted on the machine frame. The stroke of the roll stand and therewith the rollers effect a crank driving force.
In accordance with known bearing arrangements for the ring rollers of cold pilger rolling mills, labyrinth sealing rings or shaft sealing rings are used to seal the bearings. In the first case it is not possible to lubricate the bearing with oil, which is essential in the case of an ever-increasing number of rotational direction changes per unit of time in the reversing operation with superimposed horizontal acceleration and deceleration. Also the customary radial shaft sealing ring is not especially adapted for oil lubrication in these applications, since the sealing lips lift off from the sealing surfaces under the influence of acceleration and deceleration forces, so that oil escapes from the bearing and coolant as well as contaminants can enter the bearing. This leads to premature failure of the bearing.